I. Field of the Invention
The present invention concerns joint implants with diamond coated surfaces, which, in general, are useful in arthroplasty.
II. Prior Art and Problems
In the field of mechanical devices such as moving automotive and truck components it is known to diamond coat certain metal mechanical bearing surfaces. This increases their hardness and, in turn, may provide for a more friction free, longer wearing part.
In the pertinent general field of joint implants for human beings or animals, current technology includes use of a metal or ceramic ball which articulates upon a polyethylene cup, for example, of ultra high molecular weight polyethylene (UHMWPE). However, asperities on the ball component surface accelerate the loss of the polyethylene, which has been reported to be a major cause in osteolytic bone loss, with loosening and subsequent failure of the joint implant. Smoother ceramic may be employed in place of the relatively rougher metal to attempt to ameliorate the problem and provide a better joint articulation. Ceramic, however, has its own difficulties, including the requirement that more of the ceramic relative to metal must be employed to keep the ceramic part from cracking, i.e., relative bulkiness, and the proclivity of the ceramic to break, which results in more bone having to be resected, rather than being saved. Also, ceramic, although known generally to provide for a smoother surface than metal, is not entirely free from debris-causing asperities.
Certain diamond or diamond like coating methods have been disclosed, however, to be useful in making not only the metal mechanical bearing surfaces but replacement joints such as the replacement ball of a hip joint prosthesis. See, e.g., Turchan et al., U.S. Pat. Nos. 5,554,415; 5,635,243; 5,643,641; and 5,648,127. See also, QQC, Inc., WO 95/20253 (Jul. 27, 1995); Mfg. Eng., xe2x80x9cDiamond Coatings, Ready to Rip?xe2x80x9d (February 1995); and Mistry et al., Mat. Res. Innovat., 1:149-156 (1997).
It would be desirable to address and improve upon the same.
The present invention provides a diamond or diamond like coated joint implant which in general is not a femoral component for a conventional hip joint replacement prosthesis having a diamond or diamond like coated ball. The implant can be based on a metal or other suitable support material, to include, say, ceramic and plastic, which is coated with a diamond or diamond like substance, and so forth and the like, and can include heads or other convex articulating surfaces and/or sockets or other concave articulating surfaces, say, in ginglymous or enarthrodial type joints, and so forth. Beneficially, the coating is transitional in nature.
The invention is useful in arthroplasty.
Significantly, by the invention, an articulating surface of superior hardness and smoothness can be provided. Accordingly, the level of asperity-related wear debris, and the osteolytic loosening and subsequent failure of the joint as reported to be caused by the wear debris, is addressed and lessened. As well, tribological characteristics of the joint can be substantially improved, and thus, longer-lasting articulations of the implanted joints can be achieved. In the case of hemi-joint implants, more pain-free joints can be achieved.
Numerous further advantages attend the invention.